1. Field of the Invention
The present invention relates generally to fuel injection devices for internal combustion engines, and more particularly to a control of the injection quantity of such a fuel injection device which includes a booster piston for forcibly feeding fuel to a fuel injection nozzle.
2. Description of the Prior Art
Fuel injection devices of the type described are known as disclosed, for example, in Japanese Patent Laid-open Publication No. 60-95457. In the disclosed device, the movement of a booster piston is detected by a lift sensor to adjust the injection timing according to the detected signals, thereby controlling the injection quantity of the fuel injection device.
The known fuel injection device is however disadvantageous in that the overshooting of the piston which is caused by the intertia acting on the piston and the delayed action of the electric circuitry is not taken into account at all when controlling the fuel injection. With this piston overshooting, the fuel injection still continues even after the termination of a control signal to the piston.
By the way, it has been experimentally admitted that the maximum piston displacement is closely correlated with the fuel injection quantity, as shown here in FIG. 6 of the accompanying drawings.